Device for stabilizing rotary-wing aircraft



Sept. 22, 1953 ,P. E. REN-OUX 2,652,398

DEVICE FOR STABILIZING ROTARY-WING AIRCRAFT Filed July 5, 1948 8 Sheets-Sheet l Sept. 22, 1953 DEVICE FOR STABILIZING ROTARY-WING AIRCRAFT Filed Jul s, 1948 I s Sheets-Sheet 2 x g Y {fa H 3 M r I/vwsA T m'" /EPWE 5190004 23: TEA/0 P. E. RENOLVJX 2, 2, 98

Sept. 22, 1953 P. E. RENOUX 7 2,652,898

DEVICE FOR STABILIZING ROTARY-WING AIRCRAFT Filed July 5, 1948 s Sheets-Sheet 5 Sept. 22 1953 P. E. RENOUX 2,652,898

DEVICE FOR STABIL'IZING ROTARY-WING AIRCRAFT Filed July 3, 1948 I 8 Sheets-Sheet 4 ?/7P12E @aum/e Tivyaux Sept. 22, 1953 P. E. RENOUX Z,652,89

DEVICE FOR STABILIZING ROTARY-WING AIRCRAFT Filed July 3, 1948 8 Sheets-Sheet 5 Sept. 22, 1953 P. ERENOUX DEVICE FOR STABILIZING ROTARY-WING AIRCRAFT Filed July 5, 1948 8 Sheets-Sheet 7 Sept. 22, 1953 P. E. RENOUX 2,,fi52,898

DEVICE FOR STABILIZING ROTARY-WING AIRCRAFT Filed July 5, 1948 8 Sheets-Sheet 8 Zivmm-vvnw: Fae-mas fJOUflI-D Emma): (3' WW, m w a Patented Sept. 22, 1953 DEVICE FOR STABILIZING ROTARY-WING AIRCRAFT Pierre Edouard Renoux, assignor to S. A. Sooie tions Aeronautiques In France 6 Claims.

The present invention is directed to rotary wing aircraft provided with one or more rotor structures including rotor blades pivoted to a rotor hub and rotated either under the action of a source of power such as an engine or as a result of their construction in the form of jetreaction blades or the like, or further rotated in auto-rotational conditions set up by the displacement of the aircraft. Aircrafts of such type are generally known as helicopters and autogyros and will hereinafter be designated by the generic term of gyroplanes.

The invention relates to a method of stabilizing gyroplanes in flight and means for carrying said method into effect.

It is well-known that gyroplanes are subject to instability effects especially noticeable at low speeds and in stationary or hovering condition. Such instability is characterized as a tendency of the gyroplane, after having been deviated from its position of balance by any disturbance, to start oscillating with over-increasing amplitudes. This obliges the pilot to exert constant control and piloting is thus made difiicult and aircraft of such type hazardous to fly.

The principal object of this invention is to overcome those drawbacks and minimize the hazard of operating gyroplanes.

The method of the invention requires for its execution certain devices to be described hereafter and one of the chief practical features of which is that they are enormously lighter than the gyroscopic devices which it has been attempted to use heretofore in order to provide gyroplanes with flight-stability.

To facilitate understanding of this invention it will be well to define some of the chief characteristics of gyroplanes which will be referred to later on in the specification.

Fig. 1 is a diagrammatic sketch of a gyroplane illustrating the traces of the operative planes, axes, and angles of the rotor on the longiudinal plane of symmtery of the apparatus.

Fig. 2 is a similar front-end view of a gyroplane showing the traces of the operative planes, axes and angles of the rotor on a transverse plane extending through the axis of the rotorsupporting shaft, 1. e. a plane, the trace of which in Fig. l is indicated by the line II-II.

Said axis has a fixed position with respect to the body of the plane and will be termed the structural axis, being designated by the symbol No. The plane Q normal to the structural axis is referred to as the structural plane and is also fixed with respect to the body of the gyroplane. The base or piloting or control plane Aix-en-Provence, France, te Nationale de Construcdu Sud-Est Application July 3, 1948, Serial No. 86,896

February 18, 1948 P is a plane with respect to which the chord of the transverse aerofoil section of a rotor-blade profile forms a pitch-angle 0 which remains constant in that rotation of the blade.

The control or piloting axis Np is a straight line normal to the control plane P. As a general rule it is located outside of the planes of Figs. 1 and 2.

In a rotor having cyclic blade-pitch control,

the control plane is related to the position of the cyclic pitch-control mechanism by a law deriving from the kinematic relations existing between the displacements of the various blade incidence control levers, i. e. a law which derives from the construction of the gyroplane. In a tiltable rotor the control axis is the axis of the inclined or tilted portion of the hub. And the control plane is a plane perpendicular to the control axis.

The cone axis NC is the axis of the cone described by the rotor blades in operation. Generally this axis is also contained in a plane outside the planes of Figs. 1 and 2.

The projections of the axes Np and No on the longitudinal plane containing Nq respectively are Np]. and N01 (Fig. 1) while the projections on the transverse plane at right angles with said longitudinal plane are N z and N02 (Fig. 2), the corresponding traces of the planes P and Q being P1 and Q1 on the one hand and P2 and Q2 on the other. The broken lines in the same figures indicate the traces of the blades and the projections of the blade-tips, thus indicating the projection of the cone formed by the rotor-blades.

The trim angles or longitudinal control angles relating to the axes Np, No in the plane of Fig. 1 are "Yp and with respect to the structural axis.

The list angles or lateral control angles relating to said axes Np, No in the plane of Fig. 2 are 6p and 0 with respect to the structural axis.

The tilting angle of the cone axis Ne with respect to the control axis Np will be hereafter designated by a in the longitudinal plane and b in the transverse plane.

As will appear from Figs. 1 and 2 said angles are interrelated algebraically by the following equations:

The magnitude and direction of the resultant of the aerodynamic forces developed by a rotor having blade pivoted to the hub, as measured with respect to the control-plane, essentially depend on the velocity of air with respect to the control-plane, the general pitch angle, the weight of the aircraft, the weight of the blades, the rotational speed of the rotor and some other accessory parameters. In the absence of any additional devices, and if the pilot does not exert any action, the position of the control plane is fixedly related to the structural axis and therefore to the structure of the gyroplane as a whole. Consequently the direction of the resultant of the aerodynamic forces with respect to the gyroplane and also its magnitude exclusively depend on the above-mentioned factors. The values of said factors being given, it is impossible to alter at will the relative amount of stability provided by the gyroplane rotor. In other words the infiuence of the rotor upon the over all stability of the gyroplane constructed as described is also invariably determined. It is a well-known fact that in rotor structures arranged as described conventional gyroplanes are subject to instability effects particularly noticeable at low speeds and in hovering conditions.

Thus if it is desired to provide an improved condition of stability, it will be necessary artificially to modify the law which determines the magnitude and position of the resultant with respect to the gyroplane in correlation with the above-listed variables on which operation of the rotor depends. For that purpose the method used in the invention consists of subjecting the controls of the rotor or rotors (control angles '1' and 6p and general pitch angle 0) to the action of the positional variations of the cone axis with respect to the control plane, the position of which axis is characterized by the tilt angles a and b. The invention is based on the recognized fact that the resultant of the aerodynamic forces is interrelated with the blade-cone axis by a perfectly definite law; its direction is substantially that of the blade-cone axis.

It follows that if provision is made, through the use of suitable devices for the inclination of the cone axis with respect to the control plane to act upon the rotor controls, the law linking the magnitude and position with respect to the gyroplane of the resultant of aerodynamic forces of the rotor or rotors with the above-listed parameters upon which the operation of said rotor or rotors depends will be modified. Through suitably selecting the respective values and relative arrangements of the leverages of the combiner devices to be described hereinafter which are constituent elements of the stabilizing arrangement, it becomes possible to proportion at will the action exerted on the controls of the rotor or rotors by the variation in inclination of the cone axis, in such a way as to obtain any desired degree of over all stability in the gyroplane.

Other features of the invention will be made apparent in the course of the detailed description which follows which relates to various forms of embodiment of the method of the invention and devices for carrying said method into effect.

In a first form of embodiment a mechanism is provided for measuring the tilt or inclination angle of the cone described by the rotor blades and for introducing into the general pitch adjustment for the gyroplane rotor or rotors a correction the magnitude of which is a function of said angle.

In another form of embodiment there is provided a mechanism for measuring the tilt angle of the cone described by the rotor blades and introducing into the adjustment of the control plane of the gyroplane rotor or rotors a correction the value of which is a function of said angle.

A large number of combinations between both the above-defined aspects of the invention may be resorted within the scope of the invention, and the combinations which are to be described hereinafter have been selected by way of illustration and not of limitation of the manner in which the invention may be performed.

Fig. 3 is a perspective diagrammatic view of a first embodiment of a device for measuring the tilt angle of the cone axis.

Fig. 4 similarly illustrates a second embodiment of such a device.

Fig. 5 is a view in vertical cross section of a third embodiment of the same device.

Fig. 6 illustrates a first embodiment of a socalled combiner device which is a constituent of a stabilizing arrangement according to the invention.

Figs. '7 to 9 included illustrate the introduction of another form of combiner unit into a control.

Fig. 10 is a general function diagram of a complete stabilizing assembly for a gyroplane according to the invention.

Fig. 11 shows a modification of a detail of the stabilizer arrangement diagrammatically shown in Fig. 10.

Fig. 12 shows in perspective and in diagrammatic form a first form of embodiment of a gyroplane stabilizing arrangement according to the invention.

Fig. 13 is a similar showing of another form of embodiment of said arrangement.

There will first be described three forms of embodiment of the measuring device for indicating the tilt angle of the cone axis.

Fig. 3 illustrates a first form of embodiment of that device.

Each rotor connector link I of the main rotor has secured thereto a supporting bracket 2 supporting a roller 3. For greater clarity in the drawing only a single blade with its connector link has been shown, but it will be understood that the rotor shown comprises three blades spaced 120 from each other, the roller for a second blade being shown at 3a and the roller for the third blade at 31). The three rollers ride on an annulus comprising for instance a ring of steel tubing flattened in cross section and carrying a roll-way which may be formed as a strip of hard rubberized fabric stitched or adhesively secured thereto so as to provide a roll-way adapted to ensure perfect driving engagement with the rollers 3, 3a, 3b.

The annulus l is suspended at both ends of a diameter XX1 thereof from a fork member 5 pivoted to an intermediate T-shaped member 1, said fork being pivotable about an inclined axis ZZ1 of a support 8 rigidly connected with the fuselage of the gyroplane. The axis X-X1 defines With the longitudinal axis X2X3 of the gyroplane an angle defined in a manner to be described later.

The annulus t is applied against the rollers 3, 3a, 32) by springs l8 secured at one of their ends to the fuselage through a tensioning device ll making it possible to adjust their initial tension and at their other ends to lugs l'l extending from the axis Yz-Ys in an opposite direction to the arms of the fork-member 5.

The intermediate balance member 12 at both ends of which the springs it are attached is provided for the purpose of avoiding interference of the springs 18 with the oscillatory movements of the structure about the axis ZZ1. The fork 5 has suspended therefrom through pivotal connections a V-member l3 adapted through a link to operate the aircraft and which constrains it to move parallel with the axis XXl- A resilient member I6 which may comprise an elastic cord or the like provided with adjusting means effects compensation for any stresses which may be introduced into the control system by the repeater horn I4 and the devices operated by said horn.

Since in each blade the roller 3 is circumferentially spaced from the connector link I of the corresponding blade, the annulus applied against the under surface of the rollers 3, 3a and 3b is adapted to follow-up the tilt of the blade-cone with a lag or displacement corresponding to the angle included between the direction of the blade axis and that of the axis of the roller 3. It is .this angular displacement that is equal to the angle included between the axes X-Xl and Xz-Xa. In the embodiment shown the angular displacement or lag is 26; it would be quite possible however to construct a similar device wherein said angle would have a much smaller value or in which it would be equal to zero.

The oscillatory displacements of the annulus l about its suspension axis X-X1 are not measured. On the other hand the oscillatory movements effected by said annulus about the axis Y-Y1 at right angles to XX1 in the plane of the annulus 4 are adapted to rotate the V-memher about the axis ZZ1 while the vertical displacements thereof will rock the fork-member about the axis Y2Y3 parallel to the axis XX1. The inclination of the axis ZZ1 is so predetermined as to cause the rollers 3, 3a, 3b to ride upon the annulus with a minimum amount of lateral slippage.

The oscillations of the fork 5 around the axis Z-Z1 are transmitted to the V-member I3 which in turn transmits them through the link I B to the horn I4. From the horn there extends a rod or link or equivalent means adapted to transmit the variations of 'Yc to the devices on which they are supposed to act.

By way of indication merely, it may be stated that for a given type of gyroplane, and for a value of 'Yc equal to 1 degree there corresponds an inclination of 0.476 degree for the annulus 4 and an amplitude of displacement of about 0.2 inch for the end of the fork I3. Of course in such a device any play should be strictly eliminated and this may readily be provided for through various known means.

The device just described, as will be apparent, is adapted only to measure the component yr: of the tilt-angle of the cone axis on the longitudinal plane of the aircraft, account being taken of the angular displacement between X-X1 and X2-Xs.

Should it for any reason become necessary or desirable to indicate two components of the cone axis tilt-angle, it will be necessary to use a measuring device of which Fig. 4 shows one exemplary embodiment.

As shown in this figure the blade connectors I of the main rotor have universally pivoted thereto rods 22 all equal in length, the free ends slidable on a rod 24. The rod 24 is universally pivoted to the center of the rotor hub through a universal joint 25. It thus is tiltable in any direction, It follows that its direction will coincide with that of the virtual cone axis of the blades. An equal amount of upward movement in all of the blades will not affect the inclination of the rod 26 and its only result will be to cause the bush 23 to slide along the rod 24.

Thus the rod 24 is effective to indicate both the longitudinal and the lateral tilt angles of the blade-cone. To accomplish such measurement there is provided at the lower end of the rod 24 a lever 26 integral therewith and upon the universal joint element an arm 27 is provided integral with said element, the lever arm 21 being arranged to pivot about a horizontal axis at right angles to the horizontal pivotal axis of the lever arm 28. Thus the angular displacements of both lever arms 26 and 21 are adapted to indicate separately the longitudinal and the lateral tilt angles of the blade cone respectively. 28 and 29 designate rods respectively universally pivoted to the end of the levers 26 and 27 and adapted to transmit the oscillatory movements of the arms 26 and 21' to the desired controls.

The embodiment of the cone-axis tilt angle measuring device which has just been described is comparatively space-consuming in the upper part of the gyroplane. Where space requirements do not allow of such an arrangement being mounted another form of embodiment may be adopted as illustrated in a very diagrammatic manner in Fig. 5.

In this embodiment the elements necessary for measuring the cone axis tilt angle are removed to a point outside the rotor head.

The connectors I of each rotor blade are extended inwardly of the rotor hub by levers 32 the oscillatory movements of which are transmitted by a push-pull rod 33 to a circular disc 34 rotatable with the rotor. It will be seen that when the blade is raised the arm 32 is rocked downwardly and therefore the disc 3a is similarly lowered, while reversely when the blade is lowered the disc 34 will be raised. It follows that the oscillatory movements of the disc 3, will be in symmetrical or opposite relationship with those effected by the blade-tips. The disc 34 revolves in a run-way within a casing 35 the angular orientations of which are transmitted to a lever 36 integral with said casing. A suitable device not shown in the drawings is used to urge the disc 34 through the medium of its mounting 35 against the lower ends of the rod 33.

Thus the magnitudes of the longitudinal and lateral tilt angles of the cone-axis are measured by the displacements effected by the lower end of the lever 36 along two mutually perpendicular directions indicated in perspective by the arrows in Fig. 5 and each of which will therefore correspond with the measurement of the components 'yo and EC of the cone axis tilt angle.

All of the above-described devices are actually adapted to measure the inclination or tilt angle of the axis of the cone which is effectively described by the blades in their rotation, with respect to the structural axis and not the control axis.

However as shown previously a:' c+' and b:e +e. Moreover, it has been shown that 'Y and 61) are given by the cyclic pitch varying mechanism or the rotor tilting mechanism. It is only necessary therefore in order to obtain the values of a and b to additively combine the angles "y'p and as given by the rotor controls and the angles 'Yu and 6c given by the cone axis tilt angle measuring device.

For this purpose, various means may be used.

According to one embodiment of the invention to be described by way of example, a kinematic combiner unit is used, one form of construction of which is shown in Fig. 6.

As shown the rod 4| is movable lengthwise under the action of the above-described device for measuring 'Yc, while the rod 42 similarly measures "Yp- In such conditions the rod 43 will measure a, the positive values thereof being measured in the direction indicated by the twoheaded arrows in the figure. This result is obtained as follows:

A large lever 45 is pivoted on a fixed pivot 44 and the oscillations of the rod 4| are transmitted to the end 46 of the lever 45. The fixed pivot 44 also has pivotally mounted on it a bell-crank lever 48 having rectangular arms to which the movements from the rod 42 are transmitted. A similar square bell-crank lever 50 pivoted on the tree end 46 of the large lever 45 has its horizontal arm connected through a pivoted rod 49 with the end of the horizontal arm of the square bell-crank 48. The opposite end 41 of the bellcrank 50 is pivoted to the rod 43. The end of the horizontal arm of the bell-crank 50 is designated and that of the horizontal arm of the lever 48 is designated 52. It will be seen that the points 44, 46, 5| and 52 form the respective apices of a parallelogram. The bell-cranks 48 and 50 therefore always remain with their arms in respectively parallel relationship regardless of the inclination of the large lever 45. Any displacement of the push-pull rod 42 irrespective of the displacements of the rod 4| is therefore reproduced with strict fidelity by the movements of the rod 43. Similarly whenever the rod 4| is moved, the point 46 is shifted in an opposite direction by a proportionate amount and so does the point 41, but since the bell-crank 48 is not pivoted about the pin 44 when the lever 45 is pivoted under the action of the rod 4|, the vertical branch of the bell-crank 48 retains its vertical condition and consequently so does the vertical branch of the bell-crank 55. It follows that regardless of the particular position of the rod 42 any independent displacement of the rod 4| is integrally transmitted to the rod 43.

Should the rods 4| and 42 be moved simultaneously their effects will combine without however any one of said rods exerting an action on the other one and, as a result, the movements transmitted to the rod 43 effectively will be equal or proportional to the total of the displacements of the rods 4| and 42. In other words the displacements of the rod 43 do represent the total displacements 'Yc plus 71), that is a.

Figs. 8 and 9 show another form of embodiment of such a combining device as viewed in the stabilizing arrangement to be generally described somewhat later.

Said combiner is inserted in a portion, shown in Fig. '7, of a cable operated control system which it is desired to subject to the action of the longitudinal control angle for instance. Said control system includes two levers El and 63 respectively pivoted on fixed pivots B2 and 64 and rigidly connected in the rotational movements thereof through tightly stretched cables or rigid rods 6-5 and 68. 61 shows the input end from a control linkage and 68 its output towards the element to be controlled.

The device which is to be provided has to fulfill the folowing requisites:

1. If the cone-axis tilt angle remains constant, any rotation of the lever 6| should produce an equivalent rotation of the lever 63.

2. If the cone-axis tilt angle is varied, such variation should produce rotation of the lever 63 with respect to the lever 6|, said relative rotation being a function of the cone-axis tilt angle.

For that purpose it is only necessary as shown in Fig. 8 to interpose in the cables 65 and 66 an additional pair of levers of similar length 69 and i0 pivoted on fixed pins 1| and T2 respectively and interconnected through a leverage comprising the mutually pivoted rods 13, 14, 15, 16. The rods 73, 15 and 16 constitute together with the lever 10 a parallel linkage system the apices of which are 12, 82, and 83. The rod l3 will thus at all times remain parallel to the rod 16. The rod 16 is pivoted on a fixed pivot 12 and is rigid with a cam member 'I'l engaging a follower roller 18. The follower roller is adapted through a rod 19 to receive the movements of the rod 43 of the combiner unit shown in Fig. 6. A spring 84 operating in compression retains the cam 11 in constant engagement with the roller 18.

With this device the variations in the coneaxis tilt angle are expressed as or converted into rotational movements of the rod 16 and the rod 13, while the cam 11 makes it possible by suitably altering the contour of said cam to provide any desired law for transmission of the value of the cone axis tilt angle.

With this device, whenever the cone axis tilt angle or the component We used remains constant, the lever i3 constantly remains parallel with a common direction during operation of the control system SL438, because the lever 16 itself remains stationary and in engagement with the roller 53 while the rods 13 and 16 remain parallel with each other. It follows that as the levers E3 and it are swung on their pivots under the action of the identical pivotal movements of the levers 8| and E3 in response to the movements impressed on the control system 61-68, the triangle 82, 80, 8| remains undeformed and constitutes in effect a link of fixed length interconnecting the levers 69 and lil which are rotated in unison. Any rotational movement of the lever 6| is therefore transmitted to the lever 63 and the general effect is the same as if the intermediate device were absent.

If on the other hand the angle 'yc varies in value, such variation will cause a pivotal movement of the cam ll and. thereby of the rods 15 and i3 and consequently will cause a distortion of the triangle 82, 8%, 8| and assuming that in Fig. 8 the cam '51 rotates clockwise, there will result an increase in the spacing between the pivotal points 8| and 82; in other words the lever 10 will rotate relatively to the lever 69 thus introducing into the control system FF-88 a correction which will be a function of the value of the angle "Yo. This position is illustrated in Fig. 9.

The control system 61-88 may be constituted either by the general pitch control of the main rotor or the cyclic pitch control or the tilt control for the rotor or rotors of the gyroplane.

While there has so far been described by way of example an embodiment of the stabilizing method of the invention which makes use of mechanical means, it will be understood however that the invention is characterized by the feature which consists of introducing, into the control of the general pitch and the position of the control plane of the rotor or rotors of the gyroplane, a correction which is a function of the variations in the rotor cone axis tilt angle and that this feature may be embodied through the use of other than mechanical means such as electric, hydraulic or pneumatic means of various conventionally used types.

In particular the cone axis tilt angle measuring mechanism may be made to shift a slide-valve controlling a hydraulic servo-motor supplied from the pressure oil system of the gyroplane. Said servo-motor will introduce the desired correction into the controls of the rotor or rotors.

Another possible embodiment will consist of actuating through the cone axis tilt angle measuring mechanism an electric pilot member such as a potentiometer or a variable impedance or other similar means.

Said pilot member may be adapted through the use of suitable known electric circuits to control a servo-motor operative to introduce the desired correction into the controls for the rotor or rotors of the air craft. The relative importance of said correction in response to the cone axis tilt angle may be proportioned at will through selecting a suitable pattern for the parts of the hydraulic slide-valve and or the characteristics of the electric circuits, or further through any other known method of adjusting the response of a servo-control system. There may thus be obtained any desired degree of over all stability for the gyroplane.

There will now be described the general diagram of a complete gyroplane stabilizing arrangement according to the invention in its broadest aspect, as shown in Fig. 10.

In this figure IIjI designates the general pitch control 6, I92 designates the control for the longitudinal control angle 'Yp and I03 indicates the control for the lateral control angle so; I535 represents the cone described by the rotor blades;

I05 indicates the devices for measuring the cone axis tilt angle, the component 'yc of said angle bein transmitted through Itl, and the component 6a being transmitted through Hill to the combiner units Ca and Cb respectively which are adapted, on one hand, to receive the values of we and p respectively and, on the other hand, to supply as described above at the outputs thereof the values of a and b respectively, said values being transmitted through I69 and III) to the points I II and II2 and thence to the respective combiner units 0a and 0b which are eifective to combine a with 00 which latter value is supplied by the pilot through acting on the 0 control and similarly to combine b with 00. The combiners '72., 7b, 6a, eh provide for the corresponding combinations with "ypo, Epo, the latter being the respective values of the control angles as supplied by the pilot, while 'yp and 6p are the actual values efiectively produced in the corresponding elements of the aircraft.

In a gyrop-lane provided with two main rotors, the control system for the general pitch angle 0, and the control systems for the angles p and 6p are subdivided into two sections as shown in Fig. 11.

In this figure 61, 1, Epl designate the parameters relating to the first rotor while 02, pm, @112 refer to the second rotor. Where more than two rotors are present the other corresponding angles 0n, 'Ypn, 6pm relating to the Nth rotor may be determined from the controls IIII, I62, I03.

In actual practice an automatic gyroplane stabilizing device according to the invention will only exceptionally include all of the elements shown in the diagram of Fig. 10, and the embodiments described hereinafter will only comprise some of these elements. The elements selected to constitute a stabilizing device will depend on various considerations of a practical character such as the type of aircraft used, the presence or absence of auxiliary rotors and the number of such rotors if any, the type of control surfaces used and the characteristics thereof, the defects in stability inherent to the gyroplane under consideration and so on.

Fig. 12 illustrates in perspective and diagrammatically one embodiment of the stabilizing device wherein use is made in accordance with the method of the present invention of the indications provided by the device for measuring 'yo and 60, i. e. the components of the cone-axis tilt angle, for acting upon the general pitch angle 0 and the lateral angle 6p. The device will accordingly include (as see Figs. 10 and 12) the combiners Cb, 6b, 0a and 6b.

Said combiners are as shown in the general diagram of Fig. 10 inserted in the general pitch control device It" and the lateral control angle control device I03.

It will be seen in Fig. 12 that the pitch-lever or device H3 with which the pilot is provided for adjusting the value of the general pitch accomplishes such control through the medium of cables IOI passing over guide-pulleys and a control pulley II4 controlling a jack H5 which through its up-and-down movements is adapted to impart to a collar-member IIt pivotal movements in upward and downward directions around a pivotpin H8 slidable in an elongated aperture in a support bracket I I811, said collar being adapted by means of a pin II? to actuate a tube II9 coaxial with the tube I20 through which the engine of the gyroplane drives the rotor-blades I27. For that purpose the engine is connected to said shaft through any appropriate means as for instance a gearing not shown, the last driven gear of which is secured on the shaft I20, for instance, as in known constructions, on the lower end I5I of said shaft. The shaft I20 at its top supports a hub I30 to which each blade is secured through a horizontal pivot I29, a connector-link I28 and a shank I26 supporting the blade I2! itself. The shank I26 is secured to the link I28 in known manner so as to be rotatable about its longitudinal axis under the action of the general pitchadjusting mechanism and the cyclic pitch adjusting mechanism.

For that purpose, the outer tube H9 carries a horizontally extending pin I36 on which is pivoted a ring I31 around which in turn an outer ring I2I is rotatable. Between the rings I37 and IN ball members are interposed for reducing friction between said rings. The outer ring I2I is driven in rotation about the rotor axis through the use of a two-armed driv linkage I39 connecting the ring I2! with th rotor hub I30. The ring |2I carries swivel ball members I23 one for each blade around which there is swivellingly mounted a ring I22 connected through another ball-and-socket joint I24 at its opposite end with the lever I25 rigid with the blade.

It will thus be seen that as the lack H5 causes the tube III] to move up and down, said tube is operative through the pin I36 and the ring I31 to actuate the ring I2I in upward and downward movements which through the link I22 and the arm I25 are converted into pivotal movements of the rotor blade I27 about its longitudinal axis, i. e. variations in its pitch-angle. Similar devices being provided for each of the rotor blades, the

ll pitch angle of each blade will be altered a similar amount through actuation of the jack H5.

The cyclic pitch variations are effected from a control lever I3I through transverse displacements of the latter and through the control system I93 comprising cables extending over guidepulleys and over the control pulley I32 actuating a jack I33 which through a link I34 attached by means of the pivotal connection I33 to the ring I3'I, causes the latter to pivot about the pin 538 when the jack itself is moved up or down.

It follows that when the jack I33 has been displaced from the position thereof in which it maintains the ring I3! and therefore also the ring I2I horizontal, said. last-mentioned ring will be positioned in an oblique plane and the link l22 will be subjected during each revolution to an up-and-down reciprocation which through the arm I25 is converted into a cyclic variation of the pitch-angle for each rotor blade I27.

I40 designates an arm integral with the connector-link I28, said arm terminating in a ball member IfiI swivelled to a push-rod Hi2 extending through the interior of the shaft I28 and controlling at its lower end through another balland-socket joint I43 a ring I44 connected through a set of antifriction ball-members with an outerring I45 universally mounted through the medium of annulus I45 on two spigots l il each rigid with a slidable dove-tail means Hlla only one of which has been shown. The other blades comprise similar mechanisms to the means I48, I4I, I42, I43 so that the whole assembly of the abovedescribed means forms a measuring device for indicating the angle defined between the plane of the blade-tips and the structural plane.

The ring I45 terminates downwardly in a balland-socket member I48 the movements of which provide the blade cone tilt angle components.

Said components are respectively transmitted through the pivoted and. guided link I49 to the combiner 9a and through the pivoted ling I58 to the combiner Cb, thence through link I55, balance-lever H34 and link I38 to the combiner 91;. Between the ends of the link I56 there is secured a bell-crank lever I51 which through the pivoted and guided link I53 transmits the value of said component to the combiner 6b.

The combiner a is composed of a balance-lever I84 around the axis of which there is pivotably mounted a cam I85 controlled by the link I49, while at its other end th cam I55 is connected through a link [El to a rectangular bell-crank lever I88 pivoted to the opposite end of the balance lever E84 and connected through the link I68 which terminates in a follower roller with the cam I89 of the combiner 0b.

This last-mentioned combiner is made up of two similar balance-levers I19 and HI connected at each end thereof to the cables IiiI. Around the axis of the balance lever I18 there is pivoted a cam I89 connected at its lower end through a pivoted link I33 and a pivoted link I'M with one end of the balance member Il'I and through the link Hi) to the corresponding end. of the balance member I18.

The combiner Cb comprises a balance lever I52 on the pivotal axis of which there is also pivoted a T-shaped balance member I53 the intermediate arm of which has pivoted to its free end a link 55 pivotally connected at its other end with a rectangular bell-crank I54 pivoted to one end of the balance member I522. The balance member I53 has attached to the opposite ends of the larger arms thereof the respective ends of the cable I83 extending around the pulley I32.

The combiner 6b is composed of a balance member I58 having its ends attached to the ends of the section of the cable I83 which extends around a sector rigid with the control lever I3I controlling the lateral control angle. On thev pivot axis of the balance member I58 there is also pivoted a cam I62 connected at one end through a pivoted link IBI and a pivoted link I59 with one end of the balance member I58 and through another pivoted link I88 with one end of the T- shaped balance member I53. The bell crank I51 pivoted at one end to the link I56 is pivoted at its opposite end to a link I63 which supports at its other end a cam-follower roller engaging the cam I62.

It will thus be seen that between the various combiners and controls connections have thus been provided which conform to the general functional diagram of Fig. 10 and which make it possible to cause the blade-cone tilt angle variations to act both on the general pitch and the cyclic pitch control.

Through imparting the desired contour to the various cams I62, I65, I69 it is possible to vary to any required extent the degree of influence of the blade cone tilt angle on the general pitch and the cyclic pitch variations of the blades.

Fig. 13 represents a form of embodiment of a device wherein use is made only of the longitudinal cone axis tilt angle to control therefrom only the longitudinal or depth control. Accordingly this device only comprises the combiners '79. and Ca- It will be seen from Fig. 13 that by means of the control lever I8I serving for cyclic blade pitch variation adjustment, it is possible to act on said cyclic pitch variation control designated I82 in this figure through cables I83 and I84 interconnected together through the combiners 'Ya, and C9,.

The combiner Ca comprises a balance lever I85 the opposite ends of which have attached thereto the extremities of the cables I84. Said balance lever carries at I86 a pin in eccentric relation to the pivot pin I81 of the balance member I85. The pin I88 pivotally supports a bell-crank I88 connected at one end thereof through a pivotal link I89 with the longitudinal cone axis tilt angle, measuring device I98. The bell-crank I88 is connected at its other end to a pivoted link I9I which includes a swivel joint at a point intermediate its length and is suitably guided in its lower portion in a guide member I9 la. The link I9I carries at its lower end a follower roller I92 engaging a cam member I93 pivoted at I94 about the pivotal axis of the balance member I95 of the combiner 'la. The balance member I95 is at its opposite ends attached to the extremities of the cable I83. That end of the lever I93 opposite to the portion thereof which forms the cam is pivoted to a link I96 which in turn is pivoted at I9] to a link I98 the opposite end of which is pivoted to one end of the balance lever I85 and another link I99 having its free end pivoted to one end of the balance lever I95.

It will be seen that the above-described device is operative to combine the control as provided by the pilot with the control as provided by the longitudinal cone-axis tilt angle in order to cause automatic variations of the desired amplitude in the cyclic blade pitch control.

It is possible through imparting a suitable contour to the cam member I93 to obtain any desired function between the longitudinal coneaxis tilt angle and the control exerted on the cyclic variation of the rotor blade pitch.

What I claim is:

1. In a device for stabilizing in flight gyroplanes having at least one rotary wing structure tiltable with respect to a fixed line of said gyroplane and including a plurality of variable pitch blades, said device being of the kind including piloting devices which are actuatable by the pilot for controlling the general pitch and the cyclic pitch of the structures and a device connected with at least one of said piloting devices for algebraically adding to the corresponding pitch determined by the pilot a value which is a function of the variations of a total angle equal to the sum of the longitudinal component of the tilt angle of at least one of said structures with respect to said fixed line and of the longitudinal component of the control angle formed by said fixed line with the perpendicular to the control plane with respect to which the chord of the cross-section of a blade makes a constant pitch angle during the rotation of said blade, in combination, a support secured to the inner end of each blade pertaining to each structure the axis tilt angle of which is to be used, a roller rotatable on said support about an axis displaced with respect to the longitudinal axis of each blade, a tiltable annulus provided with a runway for said rollers and centered on the tiltable axis of the corresponding structure, adjustable resilient means for applying said annulus against said rollers, means for adjusting said resilient means, a fork for suspending said annulus on a diameter forming with the longitudinal axis of the gyroplane an angle equal to the angle of displacement of the rotary axes of said rollers with respect to the longitudinal axis of the corresponding blade, an intermediate T-shaped member having its opposite arms pivoted to said fork around an axis parallel with the suspension axis of said annulus, a support secured to said gyroplane for journalling the central arm of said T on an axis so determined that said rollers will be adapted to rid on said annulus with a minimum amount of lateral slippage, a V-member pivoted to said fork on each side of said intermediate member on an axis parallel with said annulus suspension axis for measuring the oscillations of said annulus about an axis located in its plane and normal to said suspension axis, means for preventing displacement of said V- member out of a plane parallel with the vertical plane extending through the suspension axis of said annulus, a control horn contained in the plane of movement of said V-member, a control system connected with said horn for controlling the device of algebraic addition, a link extending from said V-member to said horn and resilient means to compensate for the effects introduced by said horn and said control system, whereby said horn is adapted to repeat the longitudinal component of the axis tilt angle of said structure as measured by said V-member.

2. In a device for stabilizing in flight gyroplanes having at least one rotary wing structure tiltable with respect to a fixed line of said gyroplane and including a plurality of variable pitch blades, said device being of the kind including piloting devices which are actuatable by the pilot for controlling the general pitch and the cyclic pitch of the structures, and a device connected with at least one of said piloting devices for alge braically adding to the corresponding pitch de-' termined by the pilot a value which is a function of the variations of a total angle equal to the sum of the longitudinal and transverse components of the tilt angle of at least one of said structures with respect to said fixed line and of the longitudinal and transverse components of the control angle formed by said fixed line with the perpendicular to the control plane with respect to which the chord of the cross-section of a blade makes a constant pitch angle during the rotation of said blade, in combination, links pivoted at one end thereof to the inner ends of the blades pertaining to each structure the axis tilt angle of which is to be used on axes perpendicular to the longitudinal axis of said blades, a bushing slidable along the cone axis of said blades and pivotally supporting the opposite ends of said links about axes normal to said cone axis, a rod extending through said bushing and coaxial with said cone axis, a first lever rigid with and perpendicular to said rod in a plane parallel with the longitudinal plane of the gyroplane, an oscillatable support for pivoting said rod and said first lever at their point of junction about an axis perpendicular to said longitudinal plane, a second lever rigid with said support and perpendicular to said first lever, a second and fixed support to pivot said first support with said second lever at the point of junction thereof about an axis parallel to said longitudinal plane, and controls pivoted to the ends of said levers and connected with the device for algebraic summation, whereby said controls are adapted respectively to repeat the longitudinal and transverse components of said axis tilt angle as measured through said levers.

3. In a device for stabilizing in flight gyroplanes having at least one rotary wing structure tiltable with respect to a fixed line of said gyroplane and including a plurality of variable pitch blades, said device being of the kind including piloting devices which are actuatable by the pilot for controlling the general pitch and the cyclic pitch of the structures, and a device connected with at least one of said piloting devices for algebraically adding to the corresponding pitch determined by the pilot a value which is a function of the variations of a total angle equal to the sum of the component in a determined plane of the tilt angle of at least one of said structures with respect to said fixed line and of the component in said determined plane of the control angle formed by said fixed line with the perpendicular to the control plane with respect to which the chord of the cross-section of a blade makes a constant pitch angle during the rotation of said blade, in combination, levers respectively extending the longitudinal axes of the blades pertaining to each structure the axis tilt angle of which is to be used, said levers respectively having one of their ends rigid with the inner ends of said blades and being pivoted to and extending into the corresponding structure, rods parallel with the cone axis of said blades, pivoted at one end thereof to the free ends of said levers and extending under said blades, a circular disc rotatable with said structure and applied against the ends of said rods, a runway for guiding said disc, a support housing said runway, a controlling lever rigid with said support, perpendicular to the plane of said runway and parallel to the plane for which the components are to be determined, and a device connected with said controlling lever for controlling the device of algebraic summation, whereby the component of said axis tilt angle in said determined plane is measured by the displacements of said controlling lever parallel with said plane.

4. In a device for stabilizing in flight gyroplanes having at least one rotary wing structure tiltable with respect to a fixed line of said gyroplane and including a plurality of variable pitch blades, said device being of the kind including piloting devices which are actuatable by the pilot for controlling the general pitch and the cyclic pitch of the structures, and a device connected with at least one of said piloting devices for algebraically adding to the corresponding pitch determined by the pilot a value which is a function of the variations of a total angle equal to the sum of at least the component in one of the planes pertaining to a reference plane system of the tilt angle of at least one of said structures with respect to said fixed line and of at least the component in said reference plane of the control angle formed by said fixed line with the perpendicular to the control plane with respect to which the chord of the cross-section of a blade makes a constant pitch angle during the rotation of said blade, in combination, a device for measuring the tilt angle of at least one of said structures, a two-arm lever, a pivot pin for said lever, a first push-rod pivoted at one end of said two-armed lever movable in the direction of its length and connected to the axis tilt angle measuring device, a first bell crank lever pivoted to said pivot pin, a second push-rod pivoted to the end of the arm of said first bell crank lever which is perpendicular thereto, movable in the direction of its length and connected with the piloting devices, a second bell crank lever pivoted to the other arm of said first bell crank lever and having arms respectively parallel with those of said first bell crank lever, a small link connecting the end of the free arm of said first bell crank to the end of the parallel arm of said second bell crank lever, and a third push-rod pivoted to the free end of the free arm of said second bell crank lever, movable in the direction of its length and connected with the device for algebraic summation, whereby to each component of the tilt angle of the structure axis given by the measuring device is added the corresponding component of the control angle.

5. In a device for stabilizing in flight gyroplanes having at least one rotary wing structure tiltable with respect to a fixed line of said gyroplane and including a plurality of variable pitch blades, said device being of the kind including piloting devices which are actuatable by the pilot for controlling the general pitch and the cyclic pitch of the structure and a device for obtaining a total angle corresponding to the summation of at least one of the components of the tilt angle of at least one of said structures with respect to said fixed line and of the corresponding component of the control angle formed by said fixed line with the perpendicular to the control plane with respect to which the chord of the cross-section of a blade makes a constant pitch angle during the rotation of said blade, in combination, a device for measuring the tilt angle of at least one of said structures, a first lever having two equal arms, the end of one of said arms being connected with one of the piloting devices, a second lever with two equal arms similar to said first lever and parallel therewith in rest condition, the end of the arm of said second lever which corresponds to the connected arm of said first lever being connected to the device for algebraic summation, means for simultaneously connecting both said levers and altering the inclination of said second lever in response to variations in the structure axis tilt angle, and means connecting said connecting means with the rotor axis tilt angle measuring device, whereby the values of the total angle variations as transformed by the means connecting both levers is added to the pitch determined by the pilot by means of said piloting device.

6. In a device for stabilizing in flight gyroplanes having at least one rotary wing structure tiltable with respect to a fixed line of said gyroplane and including a plurality of variable pitch blades, said device being of the kind including piloting devices which are actuatable by the pilot for controlling the general pitch and the cyclic pitch of the structures and a device for obtaining a total angle corresponding to the summation of at least one of the components of the tilt angle of at least one of said structures with respect to said fixed line and of the corresponding component of the control angle formed by said fixed line with the perpendicular to the control plane with respect to which the chord of the cross-section of a blade makes a constant pitch angle during the rotation of said blade, in combination, a device for measuring the tilt angle of at least one of said structures, a first lever with two equal arms, the end of one of said arms being connected to one of the piloting devices, a second and similar lever parallel with said first lever when at rest, the end of the arm of said second lever which corresponds to the connected arm of said first lever being connected with the device for algebraic summation, a system of three rods pivoted together on a common pivot housed between both said levers, the free end of the first one of said rods being pivoted to the end of the free arm of said first lever, the free end of a second one of said rods being pivoted to the end of the corresponding arm of said second lever and the third rod having a length equal tothe distance from the pivot point of said second lever to the pivot point of said second rod to said lever, a link having a length equal to said second rod pivoted to the free end of said third rod and to the pivot point of said second lever, a cam rigid with said link pivoted on the pivot point of said second lever and having a contour which is a function of the value of the structure axis tilt angle, a link connected with the tilt angle measuring device, a follower-roller on the free end of said link engaging said cam, and resilient means applying said cam against said roller, whereby the values of the total angle variations as transformed by said cam according to the contour of the same is added to the pitch determined by the pilot by means of said piloting device.

PIERRE EDOUARD RENOUX.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,986,709 Breguet et al Jan. 1, 1935 2,415,148 Sikorsky Feb. 4, 1947 2,428,200 Campbell Sept. 30, 1947 2,443,192 Moeller June 15, 1948 2,444,070 Stanley June 29, 1948 2,529,479 Bates Nov. 14, 1950 FOREIGN PATENTS Number Country Date 892,653 France Jan. 13, 1944 

